Here comes Halloween…that time of year when everything’s coming up orange. So what better way to celebrate than to tell you about the world’s largest orange diamond, simply called “The Orange,” which will be auctioned November 12 at Christie’s Sale of Magnificent Jewels in Geneva. The 14.82-carat pear-shaped diamond is the largest Fancy Vivid Orange diamond ever to appear at auction and according to Christie’s “by far” the biggest of its kind in the world. Experts believe it could fetch upwards of $20 million, or $1.3 to $1.5 million per carat – or more!

The Orange is more than double the weight of any Fancy Vivid Orange diamond that has come to auction in modern times – and there have only been a few. The last time an orange diamond of this quality appeared at auction was at Sotheby’s in 1997. That 5.54-carat orange diamond, which became known as “The Pumpkin Diamond,” was purchased the night before Halloween by Harry Winston, for $1.3 million. In 2002, Halle Berry wore The Pumpkin Diamond, set in a ring, on the night she won the Academy Award for Best Actress for her role in Monster’s Ball.

Brooch with The Pumpkin DiamondPhoto Courtesy of Harry Winston

According to Christie’s, The Orange has been with the same owners for the last three decades (they wish to remain anonymous). Rahul Kadakia, Head of Jewelry for Christie’s Americas and Switzerland, has said the diamond’s vibrant orange color is like “the peel of an orange.”

Halle Berry wearing theHarry Winston Pumpkin Diamond Ring

The most expensive diamond ever sold at auction fetched 45.4 million francs, or $45.6 million, at Sotheby’s in Geneva in 2010. The Fancy Intense Pink diamond weighed 24.78 carats, setting the world record at $1.8 million per carat.

Could The Orange shatter that per-carat record next month at the very same auction house? Stand by and OBJ will bring you the results.